This study characterizes and establishes intermediate biomarkers for two transgenic mouse models which mimic genetic alterations intimately linked to the development of human cancer (e.g. MSH1/APC1638 and P16/Ha Ras transgenic mouse models). Such studies include gross and microscopic pathology examining tumor development, measurements of cell proliferation and apoptosis. These studies have the goal of standardizing these genetically relevant transgenic models and characterizing these models highly relevant to humans for further chemoprevention studies. The goal of the study is to evaluate the modulating effects of selected chemopreventive agents on linoleic acid metabolism and to validate these effects against ultimate cancer incidence and multiplicity in the colon.